This invention relates to a circuit for sensing a differential high voltage and more particularly to a power integrated circuit for sensing differential high voltage signals.
A common problem that exists in the field of integrated circuit technology is that of sensing or monitoring high voltage signals, especially differential high voltage signals, in view of the limited power handling capability of the integrated circuit (IC) chip. It is conventional to use a resistive voltage divider to translate the high voltage signals down to a lower level at which they can be conveniently processed by an IC voltage sensor or monitor circuit. However, the use of a resistive voltage divider entails several disadvantages which make this solution unattractive in many technological applications. For example, a resistive voltage divider results in a considerable waste of power. This power increases with the square of the voltage, thus making the overall circuit in which it is used less efficient. The resistive voltage divider also uses a considerable area of the integrated circuit chip and thereby increases the size of the IC chip, especially in the case where it is desired to sense or monitor a high differential voltage, for example, in the range of a few hundred volts. In this case, two resistive voltage dividers would be needed, making it impractical to use in an integrated circuit environment.